In recent years, digital cameras or the like have been substantially increased in resolution. As a result, the use of recording apparatuses capable of recording a high quality photographic image has been steadily increasing, in particular, ink jet recording apparatuses, which record images by jetting ink toward recording medium. There have been known various methods used for causing the ink jet recording head of an ink jet recording apparatus to jet ink droplets. Ink jet recording heads which use heat as the energy for jetting ink can be relatively easily increased in resolution, that is, the number of ink jetting nozzles. In other words, an ink jet recording head can be relatively easily improved in terms of resolution, image quality, and recording speed. In spite of the increase in the desire for high quality recording, the demand for a recording apparatus capable of recording conventional business documents and web pages has not subsided. Rather, demand has been increasing for recording apparatuses which are not only capable of recording an ordinary document at a substantially higher speed and a substantially higher level of quality than an ink jet recording apparatus in accordance with the prior art, but also, a photographic image at a substantially higher speed and at a substantially higher level of quality than an ink jet recording apparatus in accordance with the prior art.
As the means for dealing with the above described desire, various ink jet recording apparatuses have been offered in the market. One type of such ink jet recording apparatuses is characterized in that when an apparatus of this type records an ordinary document, it uses pigment black ink (Bk), that is, the ink which is high in density, and jets relatively large ink droplets, whereas when it records a web page, not only does it uses the pigment black ink (Bk), but also, cyan (C), magenta (M), and yellow (Y) inks. Further, when it records a photographic image, it uses only color inks.
Also in recent years, in order to enable an ink jet recording apparatus to record at a higher level of quality, the size of the ink droplet an apparatus jets has been further reduced. Thus, the size of an ink droplet jetted by a recent ink jet recording apparatus is as small as several pico litres; a nozzle which jets an ink droplet, the size of which is several pico litres, is roughly 10 μm in the diameter of its opening, and is as thin as 10 μm in the thickness of its wall. In order to improve an ink jet recording head, such as the above described one, in the accuracy with which the ink droplet it jets lands on recording medium, the surface of the ink jet recording head, at which the ink jetting nozzles open, is processed to make the surface repel ink (Japanese Laid-open Patent Applications 2002-355979 (Patent Document 3), 2003-266720 (Patent Document 4)). Further, for the purpose of protecting the minute opening of each nozzle of an ink jet recording head while the ink jet recording apparatus is shipped, a protective tape is pasted to the surface of the ink jet recording head, at which each nozzle opens (Japanese Laid-open Patent Applications 5-084925 (Patent Document 1), 11-348316 (Patent Document 2), and 2004-148746 (Patent Document 5)). This protective tape is to be peeled when an ink jet recording head is used for the first time.
A protective tape which is to be pasted to an ink jet recording head is made up primarily of a substrate layer and an adhesive layer. If the adhesive layer is excessively adherent, it is possible for an ink jet recording apparatus to be damaged around the openings of the nozzles when the protective tape is removed. Thus, a protective tape, the adhesive layer of which is relatively weak in adhesiveness, is sometimes used. However, if a protective tape is excessively weak in adhesiveness, it is possible that the protective tape will peel and fall off a recording head when the recording head is clamped to be conveyed or packaged while the recording head is manufactured with the use of an automatic machine. Thus, various structural arrangements which prevent the portion of a recording head, which has a protective tape, from being clamped, have been tried. However, a protective tape sometimes peeled because of the vibrations which were attributable to the conveyance of the recording head, and/or the changes in the ambient pressure attributable to the acceleration or deceleration of the recording head conveyance speed. In other words, a protective tape, the adhesiveness of which is not strong enough to possibly damage an ink jet recording head across the above mentioned areas, sometimes failed to remain satisfactorily adhered to protect the ink jet recording head.
Further, the surface of an ink jet recording head, at which the ink jetting nozzles are open, is entirely coated with an ink repellent, as described above. The presence of this ink repellent on this surface lessened the adhesion between this surface and a protective tape, resulting in the peeling of the protective tape. Even if a protective tape (adhesive layer) does not completely peel away from this surface, ink will leak; for example, even if a part of a protective tape separates from this surface by a gap of only 1 μm, ink will seep out through this gap due to the capillary action of the ink. As ink leaks, it solidifies during the shipment of the ink jet recording head, or the like occasions, causing the ink jet recording head to fail when the ink jet recording head is put to use by a user.
There are various proposals which were made to solve the above described problems. One of them (Japanese Laid-open Patent Application 2006-212796) is to process the adhesive layer of a protective layer to make the adhesive layer non-uniform in adhesiveness, in such a manner that the adhesive layer is weaker in adhesiveness across the areas in the immediate adjacencies of the opening of each nozzle, and stronger across the rest. Thus, not only can this arrangement prevent a protective tape from peeling, but also, it can prevent an ink jet recording head from being damaged across the portion immediately next to the opening of each nozzle.
This arrangement, however, requires the protective tape, which is non-uniform in adhesiveness, to be highly precisely positioned relative to a recording head when it is pasted to the recording head, possibly complicating the process for pasting the protective tape to an ink jet recording head. In addition, if this protective tape fails to be accurately positioned so that the various areas of the protective layer, which are different in adhesiveness, are correctly positioned relative to the surface of an ink jet recording head, which has the nozzle openings, it is possible that the above-described problems will occur.
The time to irradiate specific areas of a protective tape to achieve a desired level of adhesiveness between the specific areas of the protective tape and a recording head may be after the protective tape is pasted to the recording head, after the completion of the recording head. However, this arrangement complicates the manufacturing process and also requires a manufacturing apparatus of a substantial scale.